Python Opencv imshow error

Question

my code:

import cv2
img = cv2.imread("dU4fHDw-Ho.jpg", cv2.IMREAD_GRAYSCALE)

cv2.imshow('image', img)
k = cv2.waitKey(0)
if k == 27:
    cv2.destroyWindow()

And i get this error:

OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvShowImage, file /io/opencv/modules/highgui/src/window.cpp, line 583
Traceback (most recent call last):
  File "simpleopencv.py", line 4, in <module>
    cv2.imshow('image', img)
cv2.error: /io/opencv/modules/highgui/src/window.cpp:583: error: (-2) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function cvShowImage

I'm using linux mint KDE What might be the problem?

Update1: Opencv works fine with python2.7 but not working for python3.5

Update2: As it turns out running the script as Jack Gold suggested actually worked but since i already had cv2 folder in my /usr/local/lib/python3.5/dist-packages/ (which was installed using PIP i think) conflicted with the one install using the script and python3 kept using the PIP version so, I deleted that cv2 folder and restarted and everything worked fine.

Answer 1

Nothing to worry buddy,I suffered the same and this is how I got rid of this error, see if you have installed opencv via pip or pip3 or apt-get, first you gotta uninstall it

sudo pip3 uninstall (what you wrote while installing)

or sudo pip uninstall (what you wrote while installing)

or sudo apt-get remove (what you wrote while installing)

and afterwards build the opencv package from source code from github.

git clone https://github.com/opencv/opencv.git

cd ~/opencv

mkdir release

cd release

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local ..

make

sudo make install

This will solve the problem. All the best.

Answer 2

Not sure about the problem since it works fine for me. But just as an alternative, use plt.imshow() from Matplotlib, it also works fine.

Answer 3

Did you install OpenCV using pip? If you did, note that as mentioned here , this is the unofficial package for OpenCV and does not have support for GUI windows ( cv2.imshow() , etc)

I would recommend using Anaconda to install opencv using conda install -c conda-forge opencv=3.2.0 or conda install -c menpo opencv3=3.2.0

Answer 4

Easier solution is provided by conda

conda install -c loopbio -c conda-forge -c pkgw-forge ffmpeg-feature ffmpeg gtk2 opencv

You may see the following error after conda install

Traceback (most recent call last):
    File "./test.py", line 21, in <module>
      import cv2
ImportError: libopenblas.so.0: cannot open shared object file: No such file or directory

Just install openblas library would solve

yum install openblas-devel -y

Reference

[sdvillal | github] https://github.com/conda-forge/opencv-feedstock/issues/43

Answer 5

You should use absolute path to read your image.

For me on Mac OS:

img = cv2.imread('/Users/nicholasleung/Documents/after effect/AL.png')